As robotics and autonomous technology becomes more prevalent in society, this technology inevitably will interact with humans such as operators, maintenance workers, and bystanders. For example, robots in factories and other locations may work near or in cooperation with humans. These robots may be very fast and powerful relative to their human counterparts, which raises the risk of human injury or death. As a specific example, a robotic arm on a factory floor may have the strength to move heavy parts. If a worker or bystander is trapped near such a robotic arm during use or a malfunction, the person could be harmed. As another example, robots or humanoids may become part of future space missions in which they will work alongside people. These robots or humanoids will need to include safety features to keep their human counterparts safe.
Likewise, an autonomous vehicle, such as a car, a factory cart, an aircraft, a boat, or any other moving machine or autonomous object, could come in close proximity to humans during malfunction or even in normal use. For example, autonomous cars driving in congested city streets may need to navigate crowds of humans who themselves are mingling among non-human objects, such as light poles, curbs, parked vehicles, trees, or other stationary inanimate objects. Even non-autonomous vehicles and robots, such as remotely piloted vehicles or human-operated vehicles, risk injuring nearby humans. For example, user negligence or user error can result in a vehicle striking a pedestrian crossing a street. For safety's sake, such complex navigation requires that the vehicle sense and avoid humans.
In general, as humans and machines continue to interact more frequently, the risk of injury to humans will increase unless sufficient safety measures are implemented. Some existing safety measures involve touch sensors, for example. Touch sensors are reactive systems, meaning they only activate after they have already made contact with someone or something. Similarly, existing safety measures may include torque sensors or power sensors, located at joints, that detect spikes in torque or power that are indicative of impact. Those touch and impact sensors may detect impact with an object, but they do not distinguish between an inanimate object and a human or other living being.
It is desirable to have a proactive safety approach to prevent contact from happening at all. Existing proactive systems use optical cameras, infrared (IR) sensors, or ultrasonic or laser range finders, for example, to proactively sense obstacles before impact. But such sensors generally do not distinguish between humans and non-humans or inanimate objects (such as a wall or another obstacle). Moreover, if an impact occurs, existing sensors may not provide information regarding the point of impact relative to the machine. Accordingly, such sensors may fail to protect a human in an effort to protect an inanimate object.